In spite of the numerous lens elements, flare is well controlled in both Sigma zooms. (The 28-300mm zoom at 300mm setting; EOS D60 at ISO 200.)

Lens Features
Except for size, the two Compact Hyper Zooms are almost identical. Both are nicely finished in matte black with white numerals that are very legible though a bit small. As with most zoom lenses, there's no depth of field scale. The lens mount is made of metal. The zoom ring is very wide (1.5"), well ribbed, and rubberized. Though narrower (0.75"), the ribbed focus ring is adequately wide. Both zoom and focus mechanisms operate smoothly; manual focus has enough friction for a familiar feel, especially in the 28-300mm zoom. A rotation of a mere 30Þ changes focus from "macro" to infinity allowing for fast focusing. An internal focus mechanism also helps assure quick autofocus. As a bonus, the front element does not rotate; this feature is useful especially with a polarizer because the filter's effect does not change when focusing.

Both models are certainly light in weight and as small as some 28-105mm or 28-135mm zooms. When shifting from 28mm to longer focal lengths, the internal telescoping barrel extends, by 2" with the 28-200mm model and by 3" with the 28-300mm model. The internal barrel includes data on macro magnification ratios for several focal lengths, for use in extremely close focusing. There's a switch for locking the zoom ring at the 28mm position, so the internal barrel does not protrude when the lens is carried pointing downward. Frankly, this is not necessary since the zoom action is adequately stiff.

Flare is very well controlled and the corner-cut lens hood shades the front element at all focal lengths. In extreme sidelighting, at a mid-morning jousting competition, I occasionally needed to change my shooting position slightly when flare was noticeable on the viewing screen.

Even at 300mm, the Sigma 28-300mm zoom produced high image quality, especially at f/8 or f/11. As with all zooms with a maximum aperture of f/6.3 at the longest focal lengths, autofocus was not always lightning fast but remained quite reliable. (At f/8; EOS-3; Hoya polarizer; Kodak Elite Chrome 100.)

28-200mm Compact Hyper Zoom
This shorter zoom is particularly compact, so it's very portable. In spite of a 5 oz reduction in weight since the previous DL model, optical quality has been maintained. Two aspherical elements in the optical formula control distortion and enhance sharpness at the edges of the image.

The minimum focusing distance is about an inch shorter, useful for occasional nature close-up shots. Naturally, Sigma's true macro lenses produce much higher magnification and even better image quality. For the optimum results in close focusing, I stopped down to f/16. This small aperture also provided adequate depth of field to keep an entire subject within the range of acceptable sharpness. To prevent blur from camera shake, I used a tripod, but on sunny days with an ISO 400 film, a tripod may not be required.

Evaluation
At greater focusing distances, image sharpness was very high across the frame at all apertures in the 28-135mm range. There was no need to stop down from maximum aperture to increase image quality. This consistency at all f/stops is a sign of a well-designed optical formula. At longer focal lengths, center sharpness was high; stopping down to f/8 was useful for increased edge sharpness. Contrast was moderately high at all focal lengths; images that I made on a hazy day at the powwow would benefit from some contrast adjustment in Photoshop.

As suggested by the "Macro" designation, the Sigma zooms have close focusing capability. True macro lenses can produce much higher magnification, but these zooms are useful for moderate close-ups of flowers or other small subjects. (The 28-300mm zoom at 120mm; f/11; EOS D60 at ISO 200.)

As with most all-purpose zooms, I found noticeable barrel distortion (bowing outward of lines near the edge of the frame) at short focal lengths. At long zoom settings, pincushion distortion (bowing inward of lines) was noticeable. Frankly, this would be relevant only in formal architectural photography, not a typical use for a lens of this type. I noticed some light falloff (slight darkening of the corners of my slides) at wide apertures, when a polarized sky filled the frame. This is also common with wide range zooms. With this model, it may be caused by the narrower diameter of the front element. However, I applaud the designers for the smaller size because the lens accepts 62mm filters, instead of the more expensive 72mm size like its predecessor.

Autofocus Evaluation
With the EOS-3 and EOS D60, autofocus was reliable with fairly quick response and the usual high-pitched hum. In Continuous AF, the camera/lens combination had no difficulty in tracking moving Caribbean dancers and cars traveling at 30 mph. With motorcycles tearing along at higher speeds, the first frame or two of a series was not always sharp; still, some of the subsequent frames exhibit razor-sharp focus. Photographers who frequently shoot action subjects will prefer one of the (large, heavy, expensive) Sigma HSM lenses with ultrasonic focus motor and wider maximum aperture.

Mount either of the Sigma zooms on a compact SLR camera with built-in flash, and you have a small but versatile photographic system. Whenever it's inconvenient or impractical to carry a lot of gear, this combination can be a suitable alternative. (The 28-200mm zoom at 80mm; f/8; Hoya polarizer; EOS D60 at ISO 100.)

The Bottom Line
Since this 28-200mm Sigma model provides very good image quality and reliable autofocus, it would be a great choice for family and travel photography. My findings confirm Sigma's claims that the new Compact Hyper Zoom model provides higher image quality than the previous DL Hyper Zoom. For the absolutely highest image quality, shoot in the 28-135mm range. The resulting negatives or digital images should be suitable for making an excellent 8x10" print, the largest that most families want. At longer focal lengths, image quality is adequately high for an excellent 5x7" print or a good 8x10" glossy, particularly at f/8-f/16.

28-300mm Compact Hyper Zoom
This longer zoom is certainly larger and heavier, but it's a half-inch shorter and an ounce lighter than the previous DL model. Although the diameter is identical, the new Compact Hyper Zoom accepts 67mm filters instead of the larger 72mm size. (That's possible because the internal barrel is narrower.) For a zoom with such a wide range of focal lengths, it still falls into the compact category.

Because this 28-300mm extends to long focal lengths, it includes two types of special elements. This is important because the inherent optical flaws are quite different at 28mm and 300mm; both have been addressed in this lens. Two aspherical elements are used to correct "spherical aberration and coma" at short focal lengths, while an element of SLD (Super Low Dispersion) glass helps to correct "chromatic aberration" at long focal lengths. Instead of a long discussion about aberrations, I'll just say that the special elements should ensure higher edge-to-edge sharpness and help to reduce distortion.

Autofocus Evaluation
At the longest focal lengths, the maximum aperture is quite small (f/6.3). Many autofocus SLR cameras disengage autofocus when the effective maximum aperture is smaller than f/5.6. However, autofocus should continue to operate with most AF cameras, when using this Sigma model at any focal length. Thanks to an internal device in the lens, the maximum aperture information transmitted to the camera is never smaller than f/5.6. Even so, exposures remain accurate with through the lens light metering.
Because an f/6.3 aperture does not transmit much light to a camera's AF sensors, autofocus was a bit slow at long focal lengths, especially in low light or when using a polarizer. I have experienced the same problem with all f/5.6-6.3 zoom lenses. This is one of the tradeoffs for modest size and weight.

Evaluation
In terms of optical performance, this 28-300mm Sigma zoom is similar to the 28-200mm model. Images made at the widest aperture in the 28-170mm range are impressive. Again, there's no need to stop down from the maximum aperture, because image quality is quite consistent at all f/stops. The difference between the two lenses is most noticeable at the 170-200mm settings: the 28-300mm zoom produces higher sharpness across the frame at the maximum aperture.

Performance in the 200-250mm range is good at f/5.6; central sharpness is high, adequate for a fine 8x10" print. This is important because most people tend to center the subject in typical family and travel pictures. For the best edge-to-edge sharpness at any focal length from 200-300mm, it's worth stopping down to f/8 to prevent softness at the edges of the frame.

Shooting at a small f/8 aperture can cause a problem at long focal lengths, especially when using a polarizing filter. With ISO 100 film, the shutter speeds are rarely high enough to prevent blur from camera shake. For the best results when hand holding the camera, use an ISO 400 film--or the ISO 400 equivalent in a digital camera--for higher shutter speeds.

Unlike the previous 28-300mm DL Hyper Zoom, the new model offers very close focusing at all focal lengths. This can be used to fill the frame with a large blossom or for tight headshots of small subjects such as cats. I was quite satisfied with the high image quality--especially in the f/11-f/22 range typically required to maximize the range of sharp focus.

The Bottom Line
Although the 28-200mm Compact Hyper Zoom would meet most needs, some folks will prefer this 28-300mm model. The ability to select longer focal lengths can be useful for distant subjects: youngsters participating in sports events, for example. In the 28-200mm range, its optical performance is even better, useful for those who often make, or order, 8x10" prints.

Final Assessment
As with any brand, the premium-grade zooms--such as Sigma's APO EX series--produce the most impressive image quality. However, such lenses are hefty, large, and far more expensive, so they're less practical for family and travel photography. As well, they rarely cover all of the most popular focal lengths, so that means buying--and carrying--extra lenses. Understandably, there's a much higher demand for all-purpose zooms and the Sigma models will meet the expectations of most consumers.

Are you a photo enthusiast who already owns a full system? If so, you may still want to buy a 28-200mm or 28-300mm zoom for use with a compact SLR camera with built-in flash. This combination may be all you would need while hiking, cycling, skiing, or simply walking for hours on sightseeing trips. Considering their many features, modest price, and satisfying image quality, either of the Sigma models would be a great choice.

For more information, visit Sigma Corporation at www.sigmaphoto.com.

Sigma 28-300mm f/3.5-6.3
Angle Of View: 75.4 to 8.2Þ
Maximum Aperture: f/3.5-6.3
Construction: 17 elements in 15 groups
Minimum Focus Distance: 35.4"
Maximum Magnification: 1:5.1
Filter Size: 67mm
Dimensions: 3.6x3.1"
Weight: 19 oz
AF Mounts: Canon, Minolta D, Nikon D, Sigma SA
Street Price: $279